Vehicle anti-theft apparatus

A vehicle anti-theft apparatus (10), comprising:

• a valve (18) irremovably assembled to an exhaust pipe (16) of an engine (12) of the vehicle, the valve (18) comprising
• a flap (34) movable between an open position and a closed position of the exhaust pipe (16),
• a mechanical spring (24) biasing the flap (34) toward the closed position, and
• a locking pin (30) retaining the flap (34) in the open position until withdrawn;
• and
• a controller (66) configured to detect a theft event (57) and, in response, operate a solenoid (35) to withdraw the locking pin (30) from a hole (58),
• thereby releasing the mechanical spring (24) to move the flap (34) to the closed position,
• wherein the controller (66) is not configured to open the flap (34), and the flap (34) is manually openable only by a unique mechanical key (25) engageable with a shaped recess (31).